Means adapted to reduce the torsional oscillations of crankshafts



May 4, 1937. R. R. R. SARAZIN 2,079,227 MEANS AbAPTED TO REDUCE THEEO-RSIONAL OSCILLATIONS 0F CRAHKSHAFTS Original Filed July 30, 1931 FIG: 5-

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. Pisa-M... 4, 931 4 UNITED S AT-as ron sromn OSCILLATIONS or cam 's SHAFT RaoulRoland Baymond sea-1,

, Original application July so, im, serialno. 554,050. Divided and thisapplioation July 13,

- Franco December The-present application. is a division ofmy depending application Serial No. 554,056 med July 30th, 1931 wherein '13 described a means adapted to reduce the torsional oscillations of crank-shafts. a s

As is well known, thecrank-shafts of motors such as-Diesel engines, internal combustion moed to reduce the torsional oscillations of crank-shafts. 4 s A feature of said means consists of the provision of niobile to relatively to the shaft of the motor, which they constitute a kind of fly-wheel having -nega tive-inertia-relatively to torsional impulses, said so interconnected and connectedtc the shaft by'any suitable means as to ensure per- 3 manent balancing of the whole device. I

" Fly-wheels of this type may be arranged atone shaft of the motor.

Means may be provided to produce, by friction or otherwise, some damping of the angular movements of said masses.

or more points intermediate the ends of the towards or away from that .of the shaft.

-In the attached drawing, which wsby way of examples various diagrammati construc+ tional embodiments of the device according to .j the invention: p v

Fig.1 leis a cross-sectional view of an engine crankshaft with my invention, in one embodiment, applied thereto; 2, 3. and 4 are detail sectional views longitudinally of a certain; pivotaiconnection and showing three possible constructions thereofand llfigureii isadiagram 'explaining graphically the value of the radii of oscillation of the A (Fig. 1) is the-cra'nk-shaft of a Diesel or v y a d be used-to secure atight bearing; of the'nbre. or ,55

55 othermotor.

.tors and the'like, having .a variabletorque in triiiution'along their length 'inertias and resiladapted to move at an angle a A sleeve l is keyed to said shaft, having three, branches at the free end of each of which a small angular connecting rod 4 is hinged at 3,

whose two legs are set relatively ,to each other I at an angle of 120. The parallel legs of two successive angular connecting rods 4 are hinged. at! to a mass 6 and the device therefore some prises .three such masses l which constitute a kind of mobile fly-wheel.

The number of. connectingrods and w I may. of course. depart from that shown in the drawing. is v Upon shaft A revolving, the inertia of masses t causes these to inove'angularly relatively to said shaft, saldmovements causing the angular $5 connecting-rods 1, whose legsv remain always 1 parallel in pairs, tooscillate around their pivotal y axes 8. The effect of said movements of masses 6 relatively to shaft A is to counterbalance the inertia inherent to-said shaft and to exert upon the same adirectional reaction adapted to re duce its torsional oscillations.

The masses tastes an inertia means. V f It is to be'noted that the'whole of the device is balanced, whatever may be the positions of masses 6 relatively to shaft A. j The angular movements of masses 5 may be damped by the interpositionof suitable frictionalmembers at pivotal axes 3 and t. Each connecting-rod leg 4 might, forexample, nd in. a fork i (Fig. 2) S porting shaft 5. A muif I is fixed upon said shaft or pivot 5 and .between the latter mufi. and a mini 9 wedged into mass 6. ahishly compressed india rubber sleeve in iofthe silent block type,;for example) i is in- .serted. Movement of mass 8 at anangle gives Said masses-may likewise be radially movable, so that their-centres of, gravity may move to friction at its pivotal pointnwhich friction to some extent damps said movement. Q Similar-provision might bemade in regard to hlngesd.

Angular. movementsrof masses 8 might likewise be damped'by hinging directly (Fig. 3) each such mass 8 upon its pivotal axis ,5 carried by the fork or stirrup-piecev I and'by interposingh' washersof fibre. wood, asbestos fabric or like; a suitable material It on, both sides of said stin rup- -piece, between the branches of. the same and 7 mass 8. on the one--hand. and between, saidf branches and hieta'l washers 1:12, onthe other hand. Washers Jl ensure the damping fric f' 'tion,.the extent of wmoii may be adjusted at means of a spring I! and aunt 1d. Any-other known arrangement might of course mass 6.

Alternatively, each mass 6 may be made radially mobile relatively to shaft A, so that the distance of the centre of gravity of said mass relatively to the centre of the shaft may vary according to changes of angular speed, said radial movements being limited or damped by any known means, if desired.

For example, (Fig. 4) one might hinge upon, shaft 5, mounted in stirrup-piece I, a'member l5 having an extension l5 along which is adapted to move mass 6 mounted between damping springs l6, l1, whose action may be adjusted by means of a nut l8.

When a sudden variation takes place in the angular velocity of shaft A, each mass 6 tends to move away from the centre of said shaft. A

certain degree of absorption of energy by masses 6 results, such energy being restored when the speed of the shaft decreases, the final effect being to tend to correct the amplitude of the oscillations of the latter, which might still obtain.

A certain degree of radial displacement of mass 6 is permissible in the constructional embodiment shown in Fig. 2, if the indie. rubber of muff I0 is left in a condition to permit of slight further compression.

It has been ascertained that the best results were obtained by giving the radius of each hinged link of the mobile masses, a certain value resulting from the following general formula:

in which, with reference to Fig. 5 which illustrates diagrammatically the principle 'of the invention: m is the mass of one of the mobile masses 6, n is the harmonic to be compensated, r is the radius of each link 4,

a: being the distance from the centre of gravity of mass 6 to line 01 Oz joining the hinging points of links 4/1 and O the centre of the shaft under consideration.

Should the centre of gravity of the mobile mass be on the straight line 01 02, then What I claim is:

1. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, means 'for interconnecting two consecutive masses, two movable connections between each of said masses and said shaft, the connecting points between the movable connections andthe masses moving on prescribed paths.

2. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, means for interconnecting two consecutive masses, two movable connections between each of said masses and said shaft, the connecting points between the movable connections and the masses moving on prescribed paths, and means for damping the swinging of the masses with relation to the shaft.

a 3. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, dual links each connected to two of said masses, a movable connection between each link and said shaft, two of said links being connected to each mass at spaced points thereof, and means for like washers upon stirrup-piece 1 and upon damping the swinging of the masses with relation to the shaft, the connecting points between the links and the masses moving on prescribed parallel paths.

4. In a device for reducing torsional vibrations in shafts, a shaft, a pluralityof swinging masses, dual links at two points of said masses, a member rigid with said shaft, means for connecting each link with said member, and means for damping the swinging of the masses with relation to the shaft.

5. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, dual links at two points of said masses, a member .rigid with said shaft, an arm articulated on each link and fitted on said member, and means for damping the swinging of the masses with relation to the shaft.

6. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses,

dual links at two points of said masses, a member rigid with said shaft, an arm articulated on-each link and fitted on said member means for damping thev angular movement of thedual links and arranged at the articulation of each arm on the masses.

7. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, dual links at two points of said masses, 2. member rigid with said shaft, an arm articulated on each.

link and fitted on said member, means for damping the angular movement of the dual links and arranged at the articulation of each arm on the masses and damping means at the articulation of the dual link on each arm fitted on said member.

8. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, dual links at two points of said masses, a member rigid with said shaft, an arm articulated on each link and fitted on said member, resilient muffs inserted between each point of the masses and the corresponding arms of the dual links and damping means at the articulation of the dual link on each arm fitted on said member.

9. In a device for reducing torsional vibrations in shafts, a shaft, a plurality of swinging masses, dual links at two points of said masses, a member rigid with said shaft, an arm articulated on each link and fitted on said member, washers of fiber inserted between each of said two points of the masses and corresponding arms of the dual links and damping means at the articulation of the dual link on each arm fitted on said member.

10. In a device'for reducing torsional vibrations in shafts, a shaft, a plurality of swingi masses, dual links at two points of said masses, a member rigid with said shaft, an arm articulated on each link and fitted on said member, resilient muffs inserted between each of said two points of the masses and the corresponding arms of. the dual links and resilient muffs at the articulation of the dual link on each arm fitted on said member.

11. In a device for reducing vibrations in shafts, ashaft, means for mounting said shaft to rotate about an axis, a member mounted on said shaft for rotation therewith, a mass located on one side of said shaft, and two spaced means operatively connected with spaced points of said mass and with said member for guiding the spaced points of said mass to move along arcuate paths the radii of curvature of which are less than the radii of rotation of said points about the axis of rotation of the shaft, each of said means comprising an element movable with respect both to the member and'to the mass and angularly with. respect to the axis of said shaft, said means freely retaining said mass against the action of centrifugal force.

12. In a .device for reducing vibrations in shafts, a shaft, means for mounting said shaft to ,rotate about an axis, a member mounted on said shaft for rotation therewith, a mass, located on one side of said shaft, and two spaced means for connecting spaced points of said mass to said member for guiding the spaced points of said mass to move along arcuate paths the radii of curvature of which are less than the radii of rotation of said points about the axis of rotation of the shaft, each of said means comprising an element having "at least portions thereof shiftable with respect to both said mass and said member in a plane perpendicular to the axis of the shaft, said means freely retaining said mass against the action of centrifugal force.

13. In a device for reducing vibrations in shafts, a shaft, means for mounting said shaft to rotate about an axis, a member mounted on said shaft for rotation therewith, a mass situated on one side of said shaft, two spaced means connecting said mass to said member for freely retaining said mass as a bifilar pendulum suspension against the action of centrifugal effect, each of said means guiding a point of said mass along an arcuate path, the radius of curvature of which is less than the radius of rotation of said point about the axis of rotation of the shaft.

14. A device according to claim 13 in which the spaced means are identical to one another and in parallel relation so that the mass is compelled to remain always parallel to itself relatively to the member fixed to the shaft.

15. A device according to claim 13 in which the spaced means are disposed on either side of a plane passing through the axis of the shaft and the center of gravity of the mass, said means being movablejn a plane perpendicular to the axis of the shaft so that the mass is compelled to oscillate in a plane perpendicular to the axis of the shaft.

16. In a device according to claim 13 in which the spaced means are identical; to one another and are disposed in parallel relation on either side of a plane passing through the axis of the shaft and the center of gravity of the mass, said means being movable in a plane perpendicular to the axis of the shaft so that the mass is com-' pelled to remain always parallel to itself relatively to the member fixed to the shaft while oscillating in a plane perpendicular to the axis of the shaft. I

17. A device according to claim 13 in which the spaced means consist of inextensible links articulated at their inner ends on the member fixed to the shaft and at their outer end on the mass.

RAOUL ROLAND RAYMOND sARAzm. 

